Removing specific elements from JSON encoded array by use of PHP - php

Question

I have a JSON file that looks a little like this:
[
{
"uniqid":"sd54sd54f",
"Make":"Toyota",
"Start Prod":258147369,
"End Prod":369147258
},
{
"uniqid":"6sdf46sd",
"Make":"BMW",
"Start Prod":789456123,
"End Prod":159487263
},
]
What I need to do is remove an entire entry (uniqid, make, start prod and end prod) based on a uniqid that will be passed in through an HTTP POST request. So far all I have is:
$var1 = $_GET['uniqid'];
$file = 'cars.json';
$json = json_decode(file_get_contents($file), true); //im not sure if file_get_contnets is necessary...
$unset_queue = array();
foreach ( $json as $i => $item )
{
if ($item->uniquid == $var1)
{
$unset_queue[] = $i;
}
}
foreach ( $unset_queue as $index )
{
unset($json->json[$index]);
}
$json = array_values($json);
$new_json_string = json_encode($json);
When I run the code, I get no errors but the item is not removed...
EDIT: Here is the output issue at this point. Note the numbering of each car:
{"1":
{
"uniqid":"sd54sd54f",
"make":"Toyota",
"start prod":"258147369",
"end prod":"369147258"
},
"2":
{
"uniqid":"5372ab2109b05",
"make":"6sdf46sd",
"start prod":"789456123",
"end prod":"159487263"},
}
}

Answer 1

You have mentioned that you will be passing your request through HTTP POST. In that case , in order to make your code to work, you should change $var1 = $_GET['uniqid']; to $var1 = $_POST['uniqid'];

Answer 2

You can use a simple function with the JSON variable passed by reference:
function removeNode($uniqid, &$json) {
$json = json_decode($json, true); // get associative array from json
foreach($json as $key => $each) { // loop through
if($each['uniqid'] == $uniqid) // find matching unique
unset($json[$key]); // remove node from array
}
$json = json_encode($json); // re-encode array as json
}
And use like this:
removeNode('6sdf46sd', $json);
Example: https://eval.in/150341
Specific use case for you:
$var1 = $_POST['uniqid']; // you're posting the data right?
$file = 'cars.json';
$json = file_get_contents($file);
removeNode($var1, $json);
echo $json; // updated JSON
// or if you want to update the file:
// file_put_contents($file, $json);

Answer 3

Well, there are a couple of things wrong:
You are not checking that your code does what you think it does. It is important to check for errors.
You can unset the item inside the first loop. The second loop is not necessary.
Inside the second loop you are accessing an object and property that does not exist. When you decoded the JSON you specifically told it to return arrays.
First of all you should put this at the top of your script:
error_reporting(-1);
ini_set('display_errors', 'On');
That will show you every single error that occurs.
Second, you should fix your code. I just rewrote and commented your code. It is easier to show you than explain.
// Make sure that you are notified of all errors
error_reporting(-1);
ini_set('display_errors', 'On');
// Get 'uniqid' from POST/GET array; show error if
// it is not set
$var1 = filter_input(INPUT_POST, 'uniqid', FILTER_UNSAFE_RAW);
if ($var1 === null) {
die('The "uniqid" parameter is not set');
}
// Read data from file; show error if it does not work
$data = file_get_contents('cars.json');
if ($data === false) {
die('An error occurred when opening "cars.json"');
}
// Decode JSON; show error if invalid JSON
$json = json_decode($data, true);
if ( ! isset($json[0]['uniqid'])) {
die("The JSON was not decoded correctly");
}
// Go over each item in the array
foreach ($json as $key => $value) {
// If the 'uniqid' equals GET parameter
if ($value['uniqid'] == $var1) {
// Then unset it using the item's $key position
unset($json[$key]);
}
}
// Encode it again
$new_json_string = json_encode($json);
If it is a GET request then you can use this instead:
// ...
$var1 = filter_input(INPUT_GET, 'uniqid', FILTER_UNSAFE_RAW);
// ...
When you are done with the code, and you make it live, you should disable errors:
ini_set('display_errors', 'Off');
That makes sure that people cannot see the errors. Error messages often include file names and such, which is not something people should see.

Answer 4

$inputDatabase = array_values(json);